Triplex-directed control of epidermal hyperproliferation Epidermal hyperproliferation is a characteristic feature of skin cancer development, especially during the tumor promotion stage. Many of the signal transduction pathways and effector molecules involved in control of the proliferation of epidermal cells have now been identified. Furthermore, the nucleotide sequences of many of the relevant genes have been determined for both mouse and human, providing genetic targets for the development of novel strategies to control proliferation in the epidermis. The proposed research will investigate the pharmacologic potential of triplex-forming oligonucleotides (TFOs) to inhibit transcription of genes known to be involved in the proliferation of epidermal cells, including but not limited to EGFr, erbB2, src, ODC, IGF-lr, COX-2 and cyclin D1 TFOs, designed specifically to target a single site in genes of interest, will be applied locally to the constitutively hyperproliferative skin of K14 TGFalpha transgenic mice in an effort to inhibit their transcription. Therapeutic efficacy will be determined by quantitation of specific gene products by Real Time PCR and Western blotting. For those TFOs that inhibit transcription of specific genes, therapeutic effects at the phenotypic level will be evaluated by measurement of epidermal thickness, immunohistochemical visualization of proliferating cells, and TUNEL assays to assess apoptosis. The proposed experimentation will focus on "proof of principle" prior to application of this therapeutic approach to other animal model systems and extension to human skin disorders.